Puget Sound EnergyColumbia Grid PresentationJune 19, 2007John Phillips

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PSE Strategy

Meet service obligations Follow best practices for reliable, cost

efficient system Work collaboratively with stakeholders Consider all alternatives (single utility)

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Areas of Concern

Transmission capacity for Whatcom and Skagit Counties

King County capacity Cross Cascade capacity Transmission capacity for Pierce and

Thurston Counties

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BPA’s 500 kV

Monroe – Echo Lake

Winter/Spring Power Flow

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BPA’s 500 kV

Monroe – Echo Lake

Summer/Fall Power Flow

Raver - Paul

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Whatcom/Skagit Counties

South of Sedro Cut Plane operational limits Can be limiting S-N and N-S with single 230kV

line outages

New service needs New resources being proposed in US and

Canada

Changing generation and industrial loads

BPA and Snohomish in parallel

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Identified Alternatives

Sedro-Horse Ranch #2 230kV line Rebuild 30 miles of existing 115kV Utilizes existing ROW Adds third 230kV line across South of Sedro

Cutplane

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King County

Monroe-Echo Lake Cutplane BPA internal cutplane Operational limitations Highest PSE load density

North of Covington Operational limitations Growing load service needs

BPA, SCL, and Snohomish in parallel

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Monroe-Echo Lake Alternative

Sammamish-Lakeside-Talbot 230kV line Rebuild 16 miles of existing 115kV Utilize existing ROW Adds fourth 230kV line across Monroe-Echo

Lake Provide load service to North King County

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North of Covington

Covington-Berrydale 230kV project scheduled for 2008

Relieves operational limits north of Covington

Provides loop feed to PSE loads at Berrydale and Talbot

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500 KV

345 KV

N.O.

N.O.

N.O.

N.O.

230 KV

BPAMAPLE VALLEY230 KV

SCL

TALBOT

Talbot North

Talbot South

To115 kV

gridO’BRIEN

BERRYDALE

BPA COVINGTON

500 KV 500 KV

230 KV

TO TACOMA

Existing

Proposed for this project

EastBus

WestBus

Bundle 4 spans 1590 Lapwing

Existing double circuit Lapwing Extend double

circuit Lapwing

New double circuit Falcon

Future

To115 kV

grid

To115 kV

grid

To115 kV

grid

Covington – Berrydale Add 230 kV Line

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Cross-Cascades

New PSE owned wind generation in Eastern Washington

More eastern renewables expected as part of state initiative

Growing Puget Sound Load Usage change in Westside resources to

firm renewables BPA in parallel and preliminary studies are

underway

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Identified PSE Alternative

Conversion of I.P. 115kV line to 230kV Adds new 230kV line across Cascades Directly connects to wind resources Improves load service to Kittitas County Mostly on existing R.O.W.

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IP Cut-Over to 230 kV

To Rocky Reach

Kittitas12.5 kV

Hyak12.5 kV

IP 230 kV Line

Rockdale12.5 kV Easton

12.5 kVWoldale34.5 kV

Wanapum230 kV

45 MVAr

Wild Horse

BaldiWhite River

Sammamish

Maple Valley

LakeTradition

230 kV

115 kV

230 kV

Twin Falls

Cle Elum34.5 kV

230 kV

Cascade34.5 kV

Dashed are future facilities

Wind Ridge

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Pierce and Thurston Counties

New load growth pushing 230/115kV transformation capacity

Raver-Paul cutplane impacts BPA and Tacoma Power in parallel

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Pierce County Alternative

Add 230/115kV transformer at Alderton Substation

230kV source from White River or BPA Interconnection studies initiated with BPA

Provides load service to south King & Pierce Counties

Relieves Raver-Paul 115kV constraints north of Alderton

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Baldi

BPA CovingtonWhite River

Starwood

KrainCorner

Alderton

Frederick

Tacoma S.

Tacoma N.

ElectronHeights

BPAPaul

Tono

Blumaer

St Clair

GravellyLake

To BPA Olympia

To Chehalis

To BPA Grand Coulee

Raver500 kV

230 kV

500 kV

230 kV

RaverSouthInterface

287 kV

115 kV

115 kV

115 kV

230

kV

115 kV

115 kV

115 kV

115 kV

115 kV

55 kV

115 kV 230 kV

230 kV

230 kV

To West Olympia 55 kV

230 kV

500

kVTo Olympia

115 kV

Proposed for this project

Future

Existing

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Thurston County Alternative

Add 230/115kV transformer at Saint Clair or Spurgeon Creek (pending site adequacy review)

230kV source from BPA Interconnection studies being initiated with

BPA

Provides load service to south Thurston County

Relieves BPA Olympia and Tono loading

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BPA Paul

Tono

Blumaer

St Clair

GravellyLake

Chehalis500 kV

115 kV

115 kV

115 kV

West Olympia

Olympia

Plum Street

Pleasant Glade

Airport

BPA Olympia

BPATono

115 kV

115 kV

115 kV

115 kV

500 kVTo Electron Heights

287 kV

500 kV To Raver287 kV

To BPA Grand Coulee

115 kV

To Frederickson

230 kVTo Tacoma N.

To Tacoma S.230 kV

Proposed for this project

Existing

230 kV

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Additional 115kV Projects Reconductor Bellingham-Sedro Woolley

115kV lines Ties between Whatcom and Skagit Counties 4/0 CU to 1272 Bittern

Novelty 230/115kV transformer Load service to north King County

Woodland-St Clair 115kV project Adds 3rd 115kV line between Pierce and

Thurston Counties. (contingent on Timing of 230 kV projects)